1. Field of the Invention
The present invention relates to a converting circuit, and more particularly, a converting circuit capable of self-reactivation.
2. Description of the Prior Art
A converter circuit is capable of converting DC power into AC power, therefore it is often used for driving a light tube used as a light source in a display device. The converter circuit is capable of detecting whether the light tube is turned on successfully. If the light tube can't be turned on after a predetermined period of time, the protecting circuit will be initiated and then interrupts the operation of the converter circuit.
Please refer to FIG. 1. FIG. 1 is a diagram of a converter circuit 100 in a display device according to the prior art. The converter circuit 100 converts power inputted from a power source 12 to drive a light tube 11 used as a backlight source for a panel 16. The converter circuit 100 includes a power converting circuit 13, a detecting circuit 14, and a pulse width modulation (PWM) circuit 15. The power converting circuit 13 controlled by the PWM circuit 15 is used to convert the power inputted from the power source 12 into a “Vcc” voltage for turning on the light tube 11. The detecting circuit 14 is used to detect if the light tube 11 has been turned on and control the PWM circuit 15 correspondingly. If the light tube 11 has been turned on, the detecting circuit 14 will send a corresponding control signal “Sct” to the PWM circuit 15 to control the power converting circuit 13 to sustain a normal operation of the converter circuit 100. If the light tube 111 hasn't been turned on, the detecting circuit 14 will send a corresponding control signal “Sct” to the PWM circuit 15 to turn off the power converting circuit 13 thereby terminating the operation of the converter circuit 100.
In the converter circuit 100 of the prior art, if the light tube 111 can't be turned on in a predetermined period of time because of abnormal interferences, the PWM circuit 15 will be shut off, and the user has to switch off the power source 12 and then switch on the power source 12 manually to try to turn on the light tube 11, making operation highly undesirable.